Found my 6000+ rpm vibration..............

Took my 15+ year old drive shaft in to get new u-joints and a balance and Bruce said it was warped and of course outta balance plus need weight in ft that wasn't there before..........off to the track soon...........

Success! There's a couple of guys on Q&A (right now) who are having difficult balance/vibration/noise issues.

Been chasing a miss for a while and thought it was different things but will be 100% sure after I install it tomorrow to test a carb..........

I've been told there are 2 balancers for the driveshaft,low & high speed.Marty at SUPERSHAFTS http://www.supershafts.com/ has the highspeed and claims it is better than the lowspeed one if you race,especially at high RPM.

I asked him about that and he aid he has the "Cadillac" of balancers and that he spins em to around 3200 iirc but will ask again tomorrow when I pick it up...........

That warped thing is a little disturbing. Is it a stock type shaft? If it is, you are starting to push the limits of it as it is trying to "jump rope." Time to step it up to C/M!

My bad, out of round by .008-.010 and enuff to shake the dial indicator pretty badly and also needed ft. weight w/a couple welded on washers. I will install it after business stuff then test maybe later or tomorrow.............. It is CM w/1350 spicers

The driveshaft is a good thing to check on once in a while. Especially on a car that gets beat on hard. Not a bad idea to pull the driveshaft out every couple of years or so and have it spun.

No kidding and 15 years later it was like riding a hard tail above 6 grand.................lol

Tested it, yet?

Nope, no time till tomorrow morning at this point but can't wait.............Bruce mentioned POSSIBLY needing an output shaft bushing but I will drive it first............

At 15 years, yes you Most likely do need one. Change it while the shaft is out. As I recall it wasn't that hard or expensive. 15 bucs maybe ,if that.

Well unless the shaft is in already. If it is you can still grab front driveshaft yoke and move it back and forth to see how much play you have.

The trans is on 7 years..............It felt pretty good and will know for sure tomorrow.............

Feel stupid posting this w/Monte's passing but the vibration is gone and smooth as glass so next thu. at Irwindale for an all out 1/8 th pass.........went 6.15 @109 slightly lifting w/a 1.33 60 ft. Any guesses...........RIP Mr Monte Smith..........

Good luck, save the best for last
Dig out your old slips and look at the 330 , I don't think any track will kick you out based on those times

What were the changes again,weight loss and elimination of vibration???

Since last time out I found a bad coil wire so installed new wires then this vibration has been plaguing me for years but just got REAL bad. Aero tricks to relieve pressure in the rear and an air damn in ft plus removed the turbulent 6-pack scoop and finished my sealed/damned air pan.......... And 17 lbs removed fwiw............. Check out my FB pages.....Dominic Thumper or ThumperCarbs then you can see all of these changes...........

removed the turbulent 6-pack scoop and finished my sealed/damned air pan

what scoop did you replace it with?

None.........doing the yarn testing soon to verify a few things..........you'd have to go to FB to see what I mean since my I phone pics go straight to FB............

Was the 6 pac hood sealed and with a airfilter? They worked fairly decent when sealed. Saw your new style on fb, haven't seen any results with those. Don't know how it will compare. I like that your testing it though. Could be better or worse??.

Weight loss is good, as is the front lower spoiler. Your car is running better then it was before when it wasn't breaking up. So it was still picking up so I don't think you totally lost a cylinder. If it just was breaking up across the stripe, that wont have to much effect.

So, I cant put any number on it as of yet. Hope it picks up though.

I have the same goal as you Thumper, hoping to get a 5.99 or quicker ET with my pump gas small block. I believe with some of your carb tuning on my pig rich 1050 Dominator I would be a lot closer to my goal. I am looking forward to your next outing to the track to see your improvement.

I hear ya but until I get to the track we won't know........this is how we learn.......

Hey man, just call and we can fix those issues and thankxxx...........

But.... Thumpman didn't you drill holes in the back of the scoop to release some of turbulence? Sorry I don't have FB.

Dom, you've been seriously thrashing on the Dart. Physically and mentally. I think your efforts will pay off with big returns. I'm going with a 5.95x, but I want to see pics of the time slip and track security escorting you off the premises.

Been hacking away at THUMPER forever but lately the results and issues I have found should help me fly...........5.95 is a stretch so I'll say 6.000 @ 112 w/a 1.31 60 ft.............I did drill relief holes and they helped but the faster we go the LESS air opening needed just look at an Indy car or old Pro stock cars. I may go w/a 2 1/2" cowl to stiffen the hood and the top will be the bottom in my case forcing the air right into the carb which I have seen done on some fast cars..............It is faster and smoother than ever so next thu. we'll see.........